The impact of a transversus abdominis plane block including clonidine vs. intrathecal morphine on nausea and vomiting after caesarean section: A randomised controlled trial.

BACKGROUND: Intrathecal morphine (ITM) is a widely used technique for postcaesarean section analgesia but entails a high risk of postoperative nausea and vomiting (PONV). The transversus abdominis plane (TAP) block is an alternative. OBJECTIVE: We tested the hypothesis that a TAP block including clonidine reduces the incidence of PONV after caesarean section when compared with ITM. DESIGN: A randomised, controlled, double-blinded study. SETTING: Geneva University Hospitals, Switzerland, from October 2013 to February 2017. PATIENTS: A total of 182 patients undergoing elective caesarean section were studied. Reasons for noninclusion were complicated pregnancy, contraindication to spinal anaesthesia or TAP block, extreme weight or height, allergy to any medication or previous median abdominal incision. INTERVENTIONS: Patients were allocated randomly to one of two groups (quadruple blinded): 100 µg of morphine added to the spinal local anaesthetic or a bilateral TAP block with 20 ml of ropivacaine 0.375% + 75 µg of clonidine on each side. MAIN OUTCOME MEASURES: The primary outcome measure was the total number of patients presenting with PONV at 24 h. Secondary aims were to compare other adverse effects (pruritus, respiratory depression, hypotension, bradycardia, sedation), analgesic efficacy and the quality of postoperative recovery. RESULTS: At 24 h, there was no significant difference between ITM and TAP groups in the total number of patients presenting with PONV: 17/92 patients (18.5%, 95% confidence interval 11.1 to 27.9) and 27/88 patients (30.7%, 95% confidence interval 21.3 to 41.4) in TAP and ITM groups, respectively (P = 0.065). Pain scores at 6 h and cumulative morphine consumption at 24 h were lower in the ITM group (P < 0.0001 for morphine consumption at 24 h). The incidence of hypotension was higher in the TAP group (54.3 vs. 29.2%, P = 0.0006). Maternal satisfaction was high and not different between groups. CONCLUSION: A TAP block with clonidine and local anaesthetic does not reduce significantly the incidence of PONV compared with ITM. We confirm the superiority of ITM on acute postcaesarean section analgesia compared with a TAP block, even with clonidine as an adjunct. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01931215.

Prediction of Acute Postoperative Pain Following Breast Cancer Surgery Using the Pain Sensitivity Questionnaire: A Cohort Study.

OBJECTIVES: Previous studies have indicated that preoperative pain sensitivity correlates with postoperative pain intensity, and thus may be used to predict severe postoperative pain. Self-rating of pain sensitivity using the "Pain Sensitivity Questionnaire (PSQ)" may be an adjunct to these measures. METHODS: We tested the predictive ability of the PSQ as well as experimental parameters of pain sensitivity and other known risk factors for acute pain in 198 patients scheduled for breast cancer surgery. A multivariable logistic regression model was created for the binary outcome "maximum pain >3 during the first 24 hours postoperatively." RESULTS: The PSQ score proved to be an independent risk factor for at least moderate pain during the first 24 hours after surgery. Univariate analysis yielded in addition younger age, type of surgery (mastectomy vs. breast-conserving surgery), axillary dissection, expected pain, and the anxiety scores of the State-Trait Anxiety Inventory, as well as the score of the Beck Depression Inventory as risk factors. Of the experimental parameters of pain sensitivity, only the pain intensity elicited by a hot water bath was a predictor of at least moderate postoperative pain. Multivariable analysis led to a parsimonious model including only PSQ, the State-Trait Anxiety Inventory state score with a cutoff of ≥30, age with a cutoff of <55, mastectomy (vs. breast-conserving surgery), and axillary dissection. DISCUSSION: Results need to be validated in a larger cohort and for other types of surgery, but use of the simple PSQ may help to identify patients at risk of intense acute postoperative pain.

Intramolecular charge transfer in aminobenzonitriles and tetrafluoro counterparts: fluorescence explained by competition between low lying excited states and radiationless deactivation. Part II: influence of substitution on luminescence patterns.

In this paper, we study the mechanisms of charge transfer, luminescence and radiationless decay of three derivatives of 4-aminobenzonitrile (ABN): dimethyl-ABN (DMABN) and the tetrafluorinated derivatives, ABN-4F and DMABN-4F. Our CASSCF/CASPT2 computations explain the different luminescence patterns observed in these three compounds and in comparison with the parent system, ABN, in spite of their similar architecture. We have found that the modifications made by the different substitutions in ABN tune the relative energies of the locally excited (LE) and charge transfer (CT) excited states due to electronic and structural factors. In all cases, the only potentially emitting species of CT character is the twisted-ICT. The increasing stabilization of this later species in the series formed by ABN-4F, DMABN and DMABN-4F explains the increasing intensity of the anomalous emission band in these compounds. Nevertheless, other factors like probability of emission vs. nonradiative decay must have also been taken into account. In fact fluoro-substitution increases the accessibility to conical intersections of the excited states with the ground state, opening an internal conversion channel that decreases the fluorescence quantum yield in the fluorinated derivatives. Our results also show that the involvement of the π-σ* state in the CT process is only possible in ABN-4F, but even in this case it is not probable.

The peculiar spectral properties of amino-substituted uracils: a combined theoretical and experimental study.

A detailed experimental and computational study of the absorption and fluorescence spectra of 5-aminouracil (5 AU) and 6-aminouracil (6 AU) in aqueous solution is reported. The lowest energy band of the steady-state absorption spectra of 5 AU is considerably red-shifted, noticeably less intense, and broader than its counterpart in uracil (U). On the contrary, the 6 AU lowest energy absorption peak is close in energy to that of U, but it is much narrower and the transition is much more intense. The emission properties of 5 AU, 6 AU, and U are also very different. Both amino-substituted compounds exhibit indeed a much larger Stokes shift as compared to U, and the emission band of 5 AU is much narrower than that of 6 AU. Those features are fully rationalized with the help of PCM/TD-PBE0 calculations in aqueous solution and MS-CASPT2/CASSCF calculations in the gas phase. A stable minimum on the potential energy surface of the lowest energy bright state is found for 5 AU, both in the gas phase and in aqueous solution. For 6 AU a barrierless path leads to the conical intersection with the ground electronic state, but a nonplanar plateau region is predicted in aqueous solution, which is responsible for the very large Stokes shift. Some general considerations on the excited-state dynamics of uracil derivatives are also reported.

The decay from the dark npi* excited state in uracil: an integrated CASPT2/CASSCF and PCM/TD-DFT study in the gas phase and in water.

By integrating the results of MS-CASPT2/CASSCF and TD-PBE0 calculations, we propose a mechanism for the decay of the excited dark state in pyrimidine, fully consistent with all the available experimental results. An effective conical intersection (CI-npi) exists between the spectroscopic pi/pi* excited state (Spi) and a dark n/pi* state (Sn), and a fraction of the population decays to the minimum of Sn (Sn-min). The conical intersection between Sn and the ground-state is not involved in the decay mechanism, because of its high energy gap with respect to Sn-min. On the other hand, especially in hydrogen bonding solvents, the energy gap between Sn-min and CI-npi is rather small. After thermalization in Sn-min, the system can thus recross CI-npi and then quickly proceed on the Spi barrierless path toward the conical intersection with the ground state.

Theoretical investigation of luminescence behavior as a function of alkyl chain size in 4-aminobenzonitrile alicyclic derivatives.

There is still controversy about the structure of the intramolecular charge transfer (ICT) emitting species in pi-electron donor-acceptor systems that show dual fluorescence. Although the twisted ICT model is quite generally accepted, the planar ICT model is not ruled out because firm experimental evidence supports it. Among these it is the fact that some rigidized systems such as bicyclic 4-aminobenzonitrile derivatives exhibit dual fluorescence. We present here an ab initio CASSCF/CASPT2 study of a series of these compounds with the alicyclic chain ranging from 5 to 7 carbon atoms and compare their ICT mechanism with the more flexible 4-aminobenzonitrile (ABN) and 4-(dimethylamino)benzonitrile (DMABN). We present the energetics, geometries, and valence bond structures of the critical points of the potential-energy surfaces of the ground, local excited (LE), and ICT states. Our results show that the photophysical differences of the studied systems may be rationalized by two factors: the position of the ICT and LE potential-energy surfaces at the first stages of the ICT reaction and the relative energies of the excited-state minima. Computational evidence is presented that a twisted ICT structure can be adopted in some molecules such as NXC6 and NXC7 and that the anomalous band of the fluorescence spectra of these systems is emitted from a twisted ICT species.